ui.tools.operations: fix crash clicking on a model that hasn't been initialized properly.
ui.tools.operations: fix crash clicking on a model that hasn't been initialized properly.

factor/factor,nicolas-p/factor,AlexIljin/factor,slavapestov/factor,slavapestov/factor,bpollack/factor,tgunr/factor,tgunr/factor,dch/factor,tgunr/factor,nicolas-p/factor,AlexIljin/factor,mrjbq7/factor,bjourne/factor,factor/factor,bjourne/factor,bpollack/factor,dch/factor,factor/factor,bjourne/factor,factor/factor,mrjbq7/factor,AlexIljin/factor,sarvex/factor-lang,dch/factor,nicolas-p/factor,bjourne/factor,slavapestov/factor,factor/factor,dch/factor,nicolas-p/factor,slavapestov/factor,tgunr/factor,slavapestov/factor,sarvex/factor-lang,sarvex/factor-lang,bpollack/factor,bpollack/factor,bpollack/factor,nicolas-p/factor,bpollack/factor,sarvex/factor-lang,bpollack/factor,dch/factor,nicolas-p/factor,dch/factor,AlexIljin/factor,tgunr/factor,AlexIljin/factor,sarvex/factor-lang,mrjbq7/factor,bjourne/factor,slavapestov/factor,bjourne/factor,nicolas-p/factor,mrjbq7/factor,bjourne/factor,tgunr/factor,factor/factor,mrjbq7/factor,mrjbq7/factor,AlexIljin/factor,AlexIljin/factor,sarvex/factor-lang,slavapestov/factor,sarvex/factor-lang